It is generally known that high-voltage components, such as power transformers, for example, are subjected to an ageing process which can affect electrical insulation, for example. For this reason, tests, for example, on the power transformers, are required at certain time intervals in order to ensure fault-free operation of an electrical energy distribution system with such high-voltage components. Such tests give an indication of the ageing state of the insulation and also make it possible to detect other faults in the high-voltage component in question.
High-voltage components such as power transformers have a high weight, even above 100 t, depending on the rated electrical power. Transporting such a power transformer incorporated within an electrical energy distribution system into a permanently installed test station in which the transformer could be tested by means of AC voltage testing is sometimes ruled out due to the high degree of complexity involved in the transport for the respective power transformer. In addition, there would need to be sufficient redundancy in an energy distribution system for a power transformer to be capable of being removed without impairing operation of the system.
For this reason, such AC voltage tests on power transformers are increasingly performed in situ. The test arrangement with an AC voltage generator and additional components required for the test, such as a high-voltage inductor, voltage divider, and measurement and evaluation apparatuses, are transported in a plurality of assemblies to the location at which the power transformer to be tested is situated, and is installed there to form a test arrangement. The high-voltage inductor which is required for resonance testing for forming a resonant circuit with the test object is a test component of considerable size, with a height of 3 m, for example, and an inner diameter of 1 m, for example. Even the voltage divider which is required in the resonant circuit for measuring high voltages of up to 500 kV or higher, for example, is a component with a similar height.
When performing an AC voltage test, care should be taken to ensure that the components in the test arrangement have a sufficiently great distance from one another and from the adjacent ground potential owing to the high voltages which occur.
Installing the various assemblies in situ can be considerably time-consuming. EP 08010691.7 discloses a test arrangement in a container with a high-voltage inductor which can be moved out of the container and enables a compact arrangement of such a test system in situ with reduced complexity in terms of design.
In some AC voltage tests, additional protection of the high-voltage inductor against sudden changes in voltage and surges is required. This has resulted in the need for a protective apparatus to be transported separately and to be constructed in situ. Such a protective apparatus can be realized by means of a capacitive divider, for example.
Against this background, exemplary embodiments of the present disclosure provide a compact test arrangement with surge protection for the high-voltage inductor.